Azeotropic compositions of 1,1,1,3,3-pentachloropropane and hydrogen fluoride

ABSTRACT

Provided are methods for forming azeotropic or azeotrope-like mixtures of 1,1,1,3,3-pentachloro-propane (240fa) and hydrogen fluoride. Such compositions are useful as an intermediate in the production of HFC-245fa and HCFO-1233zd.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional filing from commonly owned, applicationSer. No. 13/402,983, filed 23 Feb. 2012, now U.S. Pat. No. 8,999,909,the disclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to azeotropic or azeotrope-likecompositions of 1,1,1,3,3-pentachloropropane (HCC-240fa or 240fa) andhydrogen fluoride (HF).

BACKGROUND OF THE INVENTION

Chlorofluorocarbon (CFC) based chemicals have been widely use inindustry in a variety of different applications including asrefrigerants, aerosol propellants, blowing agents and solvents, amongothers. However, certain CFCs are suspected of depleting the Earth'sozone layer. Accordingly, more environmentally friendly substitutes havebeen introduced as replacements for CFCs. For example,1,1,1,3,3-pentafluoropropane (HFC-245fa) is recognized as havingfavorable physical properties for certain industrial applications, suchas foam blowing agents and solvents, and therefore is consider to be agood substitute for the CFCs previously used for these applications.Unfortunately, the use of certain hydrofluorocarbons, includingHFC-245fa, in industrial applications is now believed to contribute tothe global warming. Accordingly, more environmentally friendlysubstitutes for hydrofluorocarbons are now being sought.

The compound 1-chloro-3,3,3-trifluoropropene, also known as HCFO-1233zdor simply 1233zd, is a candidate for replacing HFC-245fa in someapplications, including uses as blowing agents and solvents. 1233zd hasa Z-isomer and an E-isomer. Due to differences in the physicalproperties between these two isomers, pure 1233zd (E), pure 1233zd (Z),or certain mixtures of the two isomers may be suitable for particularapplications as refrigerants, propellants, blowing agents, solvents, orfor other uses.

The compound 1,1,1,2,3-pentachloropropane (240fa) is a reactant usefulin the production of both 245fa and 1233zd. Processes for making thesecompounds are well known in the art. See for example, U.S. Pat. Nos.5,763,706 and 6,844,475. See also, U.S. Patent Publication No.2011-0201853, which provides an integrated process and methods ofproducing 1233zd (E).

It has now been found that an important intermediate in the productionof both 245fa and 1233zd, is an azeotrope or azeotrope-like mixture of1,1,1,3,3-pentachloro-propane (240fa) and hydrogen fluoride (HF). Thisintermediate, once formed, may thereafter be separated into itscomponent parts, for example, by extraction or distillation techniques.HCC-240fa has a boiling point of about 178.5° C. and HF has a boilingpoint of about 20° C. at standard atmospheric pressure. These azeotropicor azeotrope-like compositions find use not only as reactor feeds in theproduction of 245fa and 1233zd, but they are additionally useful assolvent compositions useful for removing surface oxidation from metals.

SUMMARY OF THE INVENTION

The present invention is directed to azeotropic or azeotrope-likemixtures of 1,1,1,3,3-pentachloropropane (240fa) and hydrogen fluoride.Such compositions are useful as an intermediate in the production ofHFC-245fa and HCFO-1233zd.

In certain embodiments of this mixture, the composition compriseseffective amounts of 1,1,1,3,3-pentachloro-propane (240fa) and hydrogenfluoride (HF).

In certain embodiments of this mixture, the azeotropic or azeotrope-likecomposition of the invention consists essentially of from about 90 toabout 97 weight percent hydrogen fluoride and from about 10 to about 3weight percent 1,1,1,3,3-pentachloropropane (240fa), which compositionhas a boiling point of about 24° C. to about 60° C. at pressure of about17.8 psia to pressure of about 55.4 psia.

In certain embodiments of this mixture, the composition consists ofhydrogen fluoride and 1,1,1,3,3-pentachloropropane (240fa).

In certain embodiments of this mixture, the composition comprises fromabout 99 to about 1 weight percent HF.

In certain embodiments of this mixture, the composition comprises fromabout 40 weight percent to about 97 weight percent HF.

In certain embodiments of this mixture, the composition comprises fromabout 60 to about 3 weight percent 240fa.

In certain embodiments of this mixture, the composition comprises fromabout 90 weight percent to about 95 weight percent 240fa.

In certain embodiments of this mixture, the composition comprises fromabout 10 weight percent to about 5 weight percent 240fa.

In certain embodiments of this mixture, the composition has a boilingpoint of about from 24° C. to about 60° C. at a pressure from about 17.8psia to about 55.4 psia.

In certain embodiments of this mixture, the invention is directed to anazeotropic or azeotrope-like composition having about 92±2 weightpercent HF and about 8±2 weight percent 240fa has a boiling point ofabout 24° C. at 17.8 psia.

Another aspect of the present invention is directed to a method offorming an azeotropic or azeotrope-like composition which comprisesblending hydrogen fluoride and 1,1,1,3,3-pentachloropropane (240fa),which composition has a boiling point of about 24° C. to about 60° C. atpressure of about 17.8 psia to pressure of about 55.4 psia.

In certain embodiments of this method, the composition consistsessentially of from about 90 to about 97 weight percent hydrogenfluoride and from about 10 to about 3 weight percent1,1,1,3,3-pentachloropropane (240fa).

In certain embodiments of this method, the composition consists ofhydrogen fluoride and 1,1,1,3,3-pentachloropropane (240fa).

In certain embodiments of this method, the composition consistsessentially of about 92±2 weight percent HF and about 8±2 weight percent240fa and has a boiling point of about 24° C. at 17.8 psia.

Another aspect of the present invention is directed to a method offorming a heterogeneous azeotropic or azeotrope-like composition whichcomprises blending from about 0.2 to about 97 weight percent hydrogenfluoride and from about 99.8 to about 3 weight percent1,1,1,3,3-pentachloropropane (240fa), which composition has a boilingpoint of about from 24° C. to about 60° C. at pressure of about from17.8 psia to about 55.4 psia.

In certain embodiments of this method, the composition comprises fromabout 99 to about 1 weight percent HF.

In certain embodiments of this method, the composition comprises fromabout 40 weight percent to about 97 weight percent HF.

In certain embodiments of this method, the composition comprises fromabout from about 90 to about 97 weight percent HF.

In certain embodiments of this method, the composition comprises fromabout 60 to about 3 weight percent 240fa.

In certain embodiments of this method, the composition comprises fromabout 90 weight percent to about 95 weight percent 240fa.

In certain embodiments of this method, the composition comprises fromabout 10 weight percent to about 3 weight percent 240fa.

In certain embodiments of this method, the composition has a boilingpoint of about from 24° C. to about 60° C. at a pressure from about 17.8psia to about 55.4 psia.

Another aspect of the present invention is directed to a method ofseparating 240fa from the azeotropic like mixture of 240fa and HFcomprising the step of extracting the HF from the mixture.

In certain embodiments of this method, the extraction of HF isaccomplished using water or other aqueous solution.

In certain embodiments of this method, the extraction of HF isaccomplished using sulfuric acid.

In certain embodiments of this method, the extraction of HF isaccomplished by distillation.

In certain embodiments of this method, the distillation comprisesextractive distillation.

In certain embodiments of this method, the distillation comprisespressure swing distillation.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a plot of the vapor pressures of the mixtures formed inExample 1 and Example 2 as measured at 30° C. and 60° C.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a heterogeneous azeotropic compositionconsisting essentially of 1,1,1,1,3-pentachloropropane (240fa) andhydrogen fluoride (HF).

The invention further provides an azeotropic or azeotrope-likecomposition which consists essentially of from about 90 to about 97weight percent hydrogen fluoride and from about 10 to about 3 weightpercent 1,1,1,3,3-pentachloropropane (240fa), which composition has aboiling point of about 24° C. to about 60° C. at pressure of about 17.8psia to pressure of about 55.4 psia.

The invention also provides a method of forming a heterogeneousazeotropic or azeotrope-like composition which consists essentially ofblending from about 0.2 to about 97 weight percent hydrogen fluoride andfrom about 99.8 to about 3 weight percent 1,1,1,3,3-pentachloropropane(240fa), which composition has a boiling point of about—from 24° C. toabout 60° C. at pressure of about from 17.8 psia to about 55.4 psia.

When 1,1,1,3,3-pentachloropropane (240fa) and HF were added to a vessel,it was observed that 240fa forms an azeotropic or azeotrope-like mixturewith HF. The unreacted 240fa/HF intermediate was found in the vaporspace of the vessel.

The thermodynamic state of a fluid is defined by its pressure,temperature, liquid composition and vapor composition. For a trueazeotropic composition, the liquid composition and vapor phase areessentially equal at a given temperature and pressure. In practicalterms this means that the components cannot be separated during a phasechange.

For the purpose of this invention, an azeotrope is a liquid mixture thatexhibits a maximum or minimum boiling point relative to the boilingpoints of surrounding mixture compositions. An azeotrope or anazeotrope-like composition is an admixture of two or more differentcomponents which, when in liquid form under given pressure, will boil ata substantially constant temperature, which temperature may be higher orlower than the boiling temperatures of the components and which willprovide a vapor composition essentially identical to the liquidcomposition undergoing boiling.

For the purpose of this invention, azeotropic compositions are definedto include azeotrope-like compositions, which means, a composition thatbehaves like an azeotrope, i.e., has constant-boiling characteristics ora tendency not to fractionate upon boiling or evaporation. Thus, thecomposition of the vapor formed during boiling or evaporation is thesame as or substantially the same as the original liquid composition.Hence, during boiling or evaporation, the liquid composition, if itchanges at all, changes only to a minimal or negligible extent. This isin contrast with non-azeotrope-like compositions in which during boilingor evaporation, the liquid composition changes to a substantial degree.

Accordingly, the essential features of an azeotrope or an azeotrope-likecomposition are that at a given pressure, the boiling point of theliquid composition is fixed and that the composition of the vapor abovethe boiling composition is essentially that of the boiling liquidcomposition, i.e., essentially no fractionation of the components of theliquid composition takes place. Both the boiling point and the weightpercentages of each component of the azeotropic composition may changewhen the azeotrope or azeotrope-like liquid composition is subjected toboiling at different pressures. Thus, an azeotrope or an azeotrope-likecomposition may be defined in terms of the relationship that existsbetween its components or in terms of the compositional ranges of thecomponents or in terms of exact weight percentages of each component ofthe composition characterized by a fixed boiling point at a specifiedpressure.

The present invention provides a composition which comprises effectiveamounts of hydrogen fluoride and 240fa to form an azeotropic orazeotrope-like composition. By effective amount is meant an amount ofeach component which, when combined with the other component, results inthe formation of an azeotrope or azeotrope-like mixture. The inventivecompositions preferably are binary azeotropes which consist essentiallyof combinations of only hydrogen fluoride with 240fa.

In the preferred embodiment, the inventive composition contains fromabout 99 to about 1 weight percent HF, preferably from about 1 weightpercent to about 99 weight percent and most preferably from about 40weight percent to about 97 weight percent. In the preferred embodiment,the inventive composition contains from about 60 to about 3 weightpercent 240fa preferably from about 90 weight percent to about 95 weightpercent and most preferably from about 10 weight percent to about 5weight percent. The composition of the present invention has a boilingpoint of about from 24° C. to about 60° C. at a pressure from about 17.8psia to about 55.4 psia. An azeotropic or azeotrope-like compositionhaving about 92±2 weight percent HF and about 8±2 weight percent 240fahas been found to boil at about 24° C. and 17.8 psia.

EXAMPLES

The following non-limiting examples serve to illustrate the invention.

Example 1

9 g of 1,1,1,3,3-pentachloropropane (240fa) were dissolved in 14.7 g ofHF to form a heterogeneous azeotrope mixture. This experiment was doneat 24° C., and at 17.8 psia.

Example 2

Binary compositions containing solely 1,1,1,3,3-pentachloropropane(240fa) and HF are blended to form a heterogeneous azeotrope mixtures atdifferent compositions. The vapor pressures of the mixtures are measuredat about 29.9° C., 30° C. and 60° C. and the following results arenoticed.

Tables 1 and 2 show the vapor pressure measurement of 240fa and HF as afunction of composition of weight percent HF at constant temperatures ofabout 29.9° C., 30° C. and 60° C.

TABLE 1 P-T-X of 240fa/HF at T = 30° C. and 60° P (Psia) Wt. % HF T =30° C. T = 60° C. 0 0.4 0.69 9.7 21.4 53.9 17.4 21.6 54.6 91.3 21.3 55.4100 21.1 52.9

As shown in Table 1, variation of the amount of HF in the compositionshows no significant (+/−0.3 psia or less) change in pressure at 30° C.,and similarly no significant change in pressure (+/−0.8 psia) at 60° C.,supporting the azeotrope-like nature of the composition over this rangeof HF in the composition.

TABLE 2 P-T-X of 240fa/HF at T = 29.9^(c) Wt. % HF P (psia) 0 0.4 10.720.6 27.1 21.2 40.4 21.3 47.8 21.6 51.6 21.5 65.4 21.6 70.8 21.3 81.021.2 100 21.1

As shown in Table 2, variation of the amount of HF in the compositionshows no significant (+/−1 psia or less) change in pressure at 29.9° C.,supporting the azeotrope-like nature of the composition over this rangeof HF in the composition.

These data show that the mixture is an azeotrope or azeotrope-like sincethe vapor pressures of mixtures of 240fa and HF are higher, at allindicated blend proportions, than 240fa and HF alone, i.e., as indicatedin the first and last rows when HF is 0.0 wt % and 240fa is at 100.0 wt% as well as when 240fa is at 0.0 wt % and HF is at 100.0 wt. %. Thedata from Table 1 are shown in graphic form in FIG. 1.

Example 3

The azeotropic composition of the 240fa/HF mixture is also verified byVapor-Liquid-Liquid Equilibrium (VLLE) experiment.

62.6 g of 1,1,1,3,3-pentachloropropane (240fa) are dissolved in 31.6 gof HF to form a heterogeneous mixture (visual observation) at 24° C. Thevapor compositions of the mixture were sampled at room temperature of24° C. The result shows that the azeotropic composition is about 92±2 wt% HF at 24° C.

As used herein, the singular forms “a”, “an” and “the” include pluralunless the context clearly dictates otherwise. Moreover, when an amount,concentration, or other value or parameter is given as either a range,preferred range, or a list of upper preferable values and lowerpreferable values, this is to be understood as specifically disclosingall ranges formed from any pair of any upper range limit or preferredvalue and any lower range limit or preferred value, regardless ofwhether ranges are separately disclosed. Where a range of numericalvalues is recited herein, unless otherwise stated, the range is intendedto include the endpoints thereof, and all integers and fractions withinthe range. It is not intended that the scope of the invention be limitedto the specific values recited when defining a range.

It should be understood that the foregoing description is onlyillustrative of the present invention. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the invention. Accordingly, the present invention isintended to embrace all such alternatives, modifications and variancesthat fall within the scope of the appended claims.

What is claimed is:
 1. A method of forming an azeotropic orazeotrope-like composition which consists of blending from about 90 toabout 97 weight percent hydrogen fluoride and from about 10 to about 3weight percent 1,1,1,3,3-pentachloropropane (240fa), which compositionhas a boiling point of about 24° C. to about 60° C. at pressure of about17.8 psia to pressure of about 55.4 psia.
 2. The method of claim 1,wherein the composition consists of hydrogen fluoride and1,1,1,3,3-pentachloropropane (240fa).
 3. The method of claim 1, whereinthe composition consists of about 92±2 weight percent HF and about 8±2weight percent 240fa and has a boiling point of about 24° C. at 17.8psia.
 4. A method of forming an azeotropic or azeotrope-like compositionwhich consists of blending hydrogen fluoride and1,1,1,3,3-pentachloropropane (240fa), which composition has a boilingpoint of about 24° C. to about 60° C. at pressure of about 17.8 psia topressure of about 55.4 psia.
 5. The method of claim 4, wherein thecomposition comprises from about 99 to about 1 weight percent HF.
 6. Themethod of claim 4, wherein the composition comprises from about 40weight percent to about 97 weight percent HF.
 7. The method of claim 4,wherein the composition comprises from about from about 90 to about 97weight percent HF.
 8. The method of claim 4, wherein the compositioncomprises from about 60 to about 3 weight percent 240fa.
 9. The methodof claim 4, wherein the composition comprises from about 90 weightpercent to about 95 weight percent 240fa.
 10. The method of claim 4,wherein the composition comprises from about 10 weight percent to about3 weight percent 240fa.
 11. The method of claim 4, wherein thecomposition has a boiling point of about from 24° C. to about 60° C. ata pressure from about 17.8 psia to about 55.4 psia.
 12. A method ofseparating 240fa from the azeotropic like mixture of 240fa and HFconsists of the step of extracting the HF from the mixture.
 13. Themethod of claim 12, wherein the extraction of HF is accomplished usingwater or other aqueous solution.
 14. The method of claim 12, wherein theextraction of HF is accomplished using sulfuric acid.
 15. The method ofclaim 12, wherein the extraction of HF is accomplished by distillation.16. The method of claim 12, wherein the distillation comprisesextractive distillation.
 17. The method of claim 12, wherein thedistillation comprises pressure swing distillation.